1. Field of the Invention
The invention relates to a control system for a hybrid vehicle that has an internal combustion engine and a rotary electric machine for driving the vehicle and in particular to a control system for cooling a battery that receives electric power from the rotary electric machine and transmits electric power to the rotary electric machine.
2. Description of Related Art
A vehicle that includes an internal combustion engine and a rotary electric machine as prime movers for driving the vehicle, that is, a so-called hybrid vehicle has been known. In this specification, the “rotary electric machine” is used as a collective term for a motor, a generator, and further electrical equipment that functions as both of the motor and the generator. The hybrid vehicle has a battery that receives/transmits electric power from/to the rotary electric machine. Japanese Patent Application Publication No. 2014-189147 (JP 2014-189147 A) below discloses a hybrid vehicle in which a power storage amount of the battery is increased in response to a request of a vehicle user (a driver, for example).
In the case where an increase in the power storage amount is requested and the battery is thus charged, there is a high possibility that the vehicle is thereafter driven and the vehicle travels only by using the rotary electric machine. In the travel for which only the rotary electric machine is used, output of the rotary electric machine is increased. Thus, there is a case where the battery generates heat as a result of supplying a large amount of the electric power to the rotary electric machine and a temperature of the battery is increased.